In Yantai, China, I saw two Chinese sirens up close. (Molested one)
They appeared in excellent condition, no corrosion anywhere, and these are downwind of ocean air. I have seen American sirens in dry Colorado which do not look that good!
I do not believe Chinese have copied American sirens at all.
They have merely designed a most efficient model, which happens to look identical to American makes.
There is no patent infringement.
However, the "Streethawk" light bars I saw looked exactly like our two Federal Signal Streethawks.
Even the location of the logo appears exactly the same.
I assumed they were Federal Signal products.
Had my wife not stuffed our suitcases for our return, I would have considered purchasing two clear Streethawk domes there.